I'm New Here
Aug 9, 2010
ottawa on.
1977 coupe
Hi there
This is my first post on this site so here goes.
I have a 77 coupe that I have done a frame off rebuild to. It has been a fairly extensive overhaul with the object of making the car a nice enough driver to take it to the occational show. The problem with the car is the cooling systems inability to keep temperatures in a safe range.
Specifics of the car:
Original Car:1977 Coupe
350cid, th350, 3.08gear Air condtioning, most of the usual options

Current condition:
1977 coupe
New frame
Fresh 1971 LS6 454cid 420HP on engine dyno. No overheating problems.
TH 400, 3.08gear in rebuilt differential, Fuel lines upgraded to factory BB sizes, Origional 3 core rad (brass/copper) upgraded to new 4 core with auto trans cooler (brass/copper), New water pump, New hoses, new rad support (1977), fan shroud (1977) and all shroud/rad seals. No engine fan. A 1981 factory corvette electric cooling fan was installed in the shroud which runs all the time. Temperature gauge is accurate. Original chin spoiler in place, No changes to the bodywork. Origional headlights and mechanism.

What I would like to know is whether there is anybody who has some experience with different rads or different fans on their BB. C3. I have heard that the car should run ok on the highway even if there is no fan just from the ram air through the rad. I cannot do this it would overheat.
Does anyone know how many CFMs the 81 fan would move. I can get the specs for a Spal fan but I don't have any way to compare it to the factory fan. I have talked to other BB owners and have been told of the cooked foot syndrome, where they had the heater in the car blowing full to take some more heat out of the cooling system.
I have contacted a number of the aftermarket rad/fan suppliers (Dewitts, etc) but the info usually runs to a product of theirs that they say will cure 95% of all problems. I think I'm in the remaining 5%.
Anyway if there is someone out there with some real world experience with these problems I would appreciate any usefull advice.
Many thanks
Have you checked to see your a/f mixture, if its running lean even at cruising it can cause overheating problems.
This may seem a little odball but does your trans oil look burnt... If you have a bad torque converter or clutch on its way out the trans could overheat and cause the eng temp to run high. Just one more thing to check

i had a problem with that in my 71 torino with the cobra package 429 . when i was younger. the main problem was the lower rad hose collapsing,cutting of the flow of the coolant.
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I took all the insulation out from the underside of the hood....presto no more heating problems!! Good luck
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